Fan issue with AC trinary switch
 

'67 C10 with '02 LS1
I'm running the Entropy LS swap radiator with dual fans.

Fan 1 is wired to the PCM only, it triggers the relay at 195º, it works perfectly.
Fan 2 is also wired to the PCM to trigger at 205º and it's also wired to the trinary switch and connected to the same trigger (ground).

The fan will come on via the trinary switch or the PCM or both ( I assume)
I'm getting a code P0481 (fan 2) when I have the AC on and the PCM triggers the fan 2 relay. I did find a loose connector in my load center for the fan 2 relay but I fixed that.

I'm wondering if the trinary switch and the PCM fan trigger being wired together is causing the issue, and what is the best/easiest way to correct it?

Re: Fan issue with AC trinary switch
 

I rewired the fans and separated the PCM trigger and the trinary switch ground triggers

Attachment 2371446

Re: Fan issue with AC trinary switch
 

computers don't like additional stuff. you need to wire it thru a relay were its either or, not wired together.

Re: Fan issue with AC trinary switch
 

thanks....see post#2

Re: Fan issue with AC trinary switch
 

cool, thats how I was thinking just wasn't sure how to explain it!

Re: Fan issue with AC trinary switch
 

id say best bet, wire it like OE and never look back.

a/c wiring

https://lt1swap.com/pictures/99_02_s...00%20truck.gif

https://ls1tech.com/forums/attachmen...ingfansbu6.gif

fans
https://ls1tech.com/forums/attachmen...ingfansbu6.gif

https://ls1tech.com/forums/attachmen...ingfansbu6.gif
so when wired like oem, both fans run together at 1/2 speed (because both motors are powered by 1 relay). and when high speed is requested due to a/c on signal or coolant temp, both fan run at full speed since its running 1 fan on each relay seperatly.

clint